Problem with "pair_style soft"

LAMMPS LAMMPS Beginners
1

Hi All,

I am going to apply “pair_style soft” to move apart the overlapped particles. The code is run but the particles remain in their initial positions. I have read the documentation and many topics related to “pair_style”, “run”, and “fix adapt”, … . However I could not find the problem! I would be thankful if you could guide me to overcome this problem.
I have provided a simplified version of that part of my code to clarify the problem.

#*** Simulation Box
echo both
units lj
dimension 3
boundary p p p

atom_style atomic

region simbox block 0 10.0 0 10.0 0 10.0
create_box 2 simbox
create_atoms 1 random 960 733728 NULL overlap 0.1
create_atoms 2 random 240 64773 NULL overlap 0.1

mass * 1.0
velocity all create 0.5 733728 dist gaussian mom yes
timestep 0.01

#*** Preparation of initial configurations
pair_style soft 2.0
pair_coeff * * 0.0
variable prefactor equal ramp(0,10)

fix 1 all adapt 1 pair soft a * * v_prefactor
dump dump1 all xyz 100 dump.xyzAl
run 10000
undump dump1
unfix 1

2

Please look at your output or log file more carefully. Do you see any warnings? You should see at least one and that one is one you should not ignore. That will also explain why atoms are not moving.

3

Thank you Axel for reminding me this. I found it. It needs a fix to be integrated.